Does platelet-rich plasma for the knee work?

Platelet-rich plasma makes it possible to heal painful knee injuries, using a person's own blood.

Athletes such as Tiger Woods and Rafael Nadal are rumored to have undergone a relatively new treatment that involves injections of platelet-rich plasma. Proponents say the therapy offers cutting-edge treatment for previously debilitating injuries, including painful knee problems due to osteoarthritis.

What is platelet-rich plasma?

Platelet rich blood plasma from the patient will be injected into the knee as part of the treatment.

Platelets are fragments of cells in the blood and are best known for their ability to help the blood clot. However, they also contain a variety of proteins called growth factors.

Platelet-rich plasma therapy is built on the notion that these growth factors can support healing. The process, which uses the person's own blood, involves separating the blood cells from the plasma, the liquid part of the blood. The process increases the number of platelets, which are then put back into the plasma.

This plasma now contains a higher than usual concentration of platelets, which a doctor can inject into an area damaged by disease and injury.

Research has shown that platelet-rich plasma can help with knee pain, and may be particularly helpful for those who have had no success with other treatments.

Although researchers think that growth factors play a role in healing, it is unclear precisely how platelet-rich plasma aids healing. It does not work for everyone, but people who see improvements usually experience healing over several weeks.

Among people who experience a reduction in pain after protein-rich plasma treatment, the results are usually permanent. However, some people may need follow-up treatments if their pain returns.

Protein-rich plasma knee treatment vs. platelet-rich plasma?

Some articles about platelet-rich plasma talk about protein-rich plasma. This can be confusing, but the two terms mean basically the same thing

Both blood platelets and plasma are rich in proteins. These proteins include growth factors and numerous other compounds that can support healing. So, regarding definition, either term is acceptable.

Does platelet-rich plasma knee treatment work?

Platelets in the blood are what help with blood clotting, they also contain growth factors that may help healing.

Although platelet-rich plasma injections are a relatively new treatment, preliminary research suggests that they can be very effective for knee pain.

A 2009 study evaluated the effects of platelet-rich plasma injections on 100 people with degenerative cartilage lesions in their knees. Participants saw significant improvements in pain 6 months after the treatment.

At 12 months, the participants had begun to experience pain again. This suggests that some recipients of platelet-rich plasma injections may need follow-up treatment.

A 2012 study of 120 patients with various degrees of knee osteoarthritis compared platelet-rich plasma injections to injections with hyaluronic acid. The people who had platelet-rich plasma injections experienced greater improvements in pain and functioning.

A 2013 study followed 78 patients with osteoarthritis in both knees. Compared with a group that received placebo injections, people that received platelet-rich plasma injections also experienced significant reductions in pain.

Most people saw results within a few weeks and continued to experience pain relief for the entire 6 months of the study. At the 6-month mark, however, most had begun to experience pain again.

Other studies have found that platelet-rich plasma can effectively treat injuries in other areas of the body. For instance, a 2006 study found a 60 percent improvement in elbow tendinosis in people who underwent platelet-rich plasma injections.

Most studies have found few or no side effects, and suggest that platelet-rich plasma is a safe, less invasive alternative to knee surgery. Because injections involve the person's own blood, an allergic or other adverse reaction is less likely than with other injections.

What to expect during and after treatment

A knee brace or splint may be recommended after platelet-rich blood plasma treatment, alongside rest and gentle physical therapy.

Treatment begins when a doctor draws blood from a vein, usually in the arm. The blood is separated out to create the platelet-rich plasma, which a doctor injects directly into the area in need of treatment.

This process sometimes requires the use of an ultrasound machine. An ultrasound image helps the doctor find the right injection site. The ultrasound is painless. During the procedure, a doctor or technician will put gel on the skin and place an ultrasound device on the area of the injection.

Some people worry about pain. Drawing blood is usually only mildly painful with a quick, sharp sticking sensation. Some people feel dizzy when their blood is drawn.

The injection itself may hurt, depending on how sensitive the joint is and the precise location of the injection. Relaxing and deep breathing may help reduce pain. The injection itself takes only 1-2 minutes.

The injection site might be tender after the injection, but should not be painful. Some people develop a bruise or small wound at the site of the injection.

In the weeks after the injection, the following steps can increase the likelihood that treatment will work:

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